buildflycrash

Ignition noise -Crash course needed.

DA 50 on QQ 85" Yak. Ignition and three Li Ions on the engine box. receiver (futaba PCM) about 16" back behind the wing tube. MPI regulator switches. I haven't started the engine yet so I don't know if there is a problem. I have herd about ignition noise and I want to do what I can Now.

I am still about 3/4" tail heavy so moving the Batteries will mean adding weight. I hate Lead.

Rcpilot

My Feedback: (78)

Do a range check on it. Engine OFF and then engine ON. Use a PPM RX to check it. If it's all good-- THEN put your PCM RX in it.

I'm one of those guys who sticks to the 12" rule when it comes to ignitions and receivers. I always keep my RX, servos, switches and my RX batteries at least 12" from anything related to the ignition. But, I just recently ended up putting a throttle and choke servo an inch away from an ignition battery, switch, and ignition unit. I was worried about it. I started a thread about it to ask for advice too. I mean I was WORRIED.

I ended up putting RF chokes on the leads for the throttle and choke servos.

Then I just did a good rande check with it. First I walked away with the engine off. No ignition. Plane on. Got at least 150' with antenna down. Could have gone farther, but I was satisfied with a 150' range check. Came back and started the engine. Same range check. Not a single glitch. I should have kept walking away untill it glitched, but didn't reallt think it was necessary. 150' away at various throttle settings. Antenna down. Rock solid servos. Good enough.

I'm using Hitec PPM 8ch RX.

I'd suggest you just try it. Use a PPM RX if you have one. It won't hide any glitches like a PCM will. That way you KNOW it's good and solid. Or, if it gitters, you know it's all messed up and you can start working the problem. If you get a solid range check from it--then switch over to your PCM RX if you want too.

You might be surprised.

If you have problems, I'd start moving those RX batteries away from the ignition box. Go back to the 12" rule and try to isolate the RX components from the ignition.

Good luck.

buildflycrash

thanks
the ppm receiver is a good idea, thats easy enough to do.
I have seen the plug wire wrapped in a plastic shield - is that nessesary?


Any other tips?

pe reivers

the plug wire (high tension lead) must be protected, because the shielding also is the earth connection of the ignition. Should that fail the ignition goos POOF, because the spark energy has no way to go.

Modern fully enclosed ignitions are extremely well shielded for RF interference. Not so the batteries and battery wiring, which may radiate some due to the high tension cirquit charge current pulses. It is to be observed, that the ignition manufacturers stick to the 10" rule minimum distance. They know their stuff.

Like RCpilet said, always do an antenna down check with a ppm system that does not hide interference pulses.

buildflycrash

Now in english?

Rcpilot

My Feedback: (78)

The igniton unit pulls energy from the battery in small pulses. Then it runs the energy through a coil to amplify it before it shoots it down the plug lead.

Those pulses coming out of the battery and into the ignition unit can bleed out RF interference.

Thats why it's always a good idea to keep your ignition betteries away from your RX batteries and RX switches too. That little bit of RF that may bleed out of the power lead between the ignition battery and the ignition unit could possibly bleed into the battery leads on your RX batteries and thereby transfer into the RX.

BSR

My Feedback: (2)

ok here is one for you, brisson 3.2 all elec are foward on an ultimate 1.60 rec@ battery are 14in away. did range check with radio on and got 200ft. with radio on and motor running the rudder glitches at only 50to60ft what to do, sure can use som advice

dirtybird

My Feedback: (5)

Check the ignition system over carefully. Make sure all connections are clean, the grounds are tight and there is no breaks in the shielding. Be sure to use a resistor spark plug if available in the size your engine takes. Try a new spark plug, a new ignition battery and a new ignition switch. If all else fails return the ignition module to the manufacturer for spark plug lead replacement.

BillS

Including receiver?

Bill

BillS

The plug wire and cap on the DA’s that I have checked emit so little RF that my inductive tack will not pick up a signal. It indicates that DA ignition is very quiet.

I would not put all the batteries together. The rebuild will probably add all the weight needed.

Bill

BSR

My Feedback: (2)

what is strange is that all equipt was taken out of a large mig3 and put into the ultimate with no rfi in mig, somebudy said that it might be vibration i dont think so. i already talked to chi to have a shielded plug cover , but he doesint think that is it

crfabbro

My Feedback: (56)

Instead of using a FM rx to test for glitches try programming your fail-safe with a little rudder, elevator and
low throttle. I use this method and the plane will always give you a sign when there is a problem. chris

BillS

There is nothing strange about moving equipment and then experiencing a problem. Both vibration and equipment location (proximity to other components) and antenna location will modify the little RF’s behavior.

Bill

Antique

My Feedback: (4)

crfabbro, NO, NO, NO !!!!! Do the range check described by Rcpilet above, post #2, never put a plane in the air to check out things you should have done on the ground. Way to dangerous to yourself and others.